diff --git a/simulai/optimization/_optimization.py b/simulai/optimization/_optimization.py
index 912300a0..6c04207a 100644
--- a/simulai/optimization/_optimization.py
+++ b/simulai/optimization/_optimization.py
@@ -303,7 +303,7 @@ def _seek_by_extra_trainable_parameters(
                 for c in residual.trainable_parameters.values()
                 if isinstance(c, Parameter)
             ]
-            if c:
+            if extra_parameters:
                 print("There are extra trainable parameters.")
             return extra_parameters
         else: